General Cox’s division, which had been ordered up to support General Pleasanton, left its bivouac, near Middletown, at six, A. M. The First brigade reached the scene of action about nine, A. M. and was sent up the old Sharpsburgh road, by General Pleasanton, to feel the enemy and ascertain if he held the crest on that side in strong force. This was soon found to be the case; and General Cox having arrived with the other brigade, and information having been received from General Reno that the column would be supported by the whole corps, the division was ordered to assault the position. Two twenty-pounder Parrotts of Simmons’ battery and two sections of McMullen’s battery were left in the rear in position near the turnpike, where they did good service during the day against the enemy’s batteries in the gap. Colonel Scammon’s brigade was deployed, and, well covered by skirmishers, moved up the slope to the left of the road with the object of turning the enemy’s right, if possible. It succeeded in gaining the crest and establishing itself there, in spite of the vigorous efforts of the enemy, who was posted behind stone walls and in the edges of timber, and the fire of a battery which poured in canister and case-shot on the regiment on the right of the brigade. Colonel Crooke’s brigade marched in columns at supporting distance. A section of McMullan’s battery, under Lieutenant Croome, (killed while serving one of his guns,) was moved up with great difficulty, and opened with canister at a very short range on the enemy’s infantry, by whom (after having done considerable execution) it was soon silenced and forced to withdraw. One regiment of Crooke’s brigade was now deployed on Scammon’s left, and the other two in his rear, and they several times entered the first line and relieved the regiments in front of them when hard pressed. A section of Sumner’s battery was brought up and placed in the open space in the woods, where it did good service during the rest of the day. The rebels made several ineffectual attempts to retake the crest, advancing with great boldness, but were on each occasion completely repulsed. Pretty hot fighting had now been going on for about six hours—the battle having began at six o’clock in the morning. About noon, a lull occurred in the contest, lasting nearly two hours; during which the rebels had withdrawn their batteries considerably to the right, and formed columns on both the Union army’s flanks; while the rest of the Union forces were coming up. General Wilcox’s division was the first to arrive, and took position on the right, having, however, sent one regiment to the extreme left to assist that point against the rebels, who were moving against it. The division of General Sturgis supported General Wilcox; that of General Rodman was divided, the brigade of Colonel Fairchild being posted on the extreme left; and that of Colonel Hanlan (under General Rodman’s own supervision), on the right.